Stun Damage
From 5punk Wiki
Stun Damage is the Shadowrun term for damage you take which only stuns you, rather than, for instance, makes a hole in your torso. Things like being punched or drugged do stun damage.
When you hit a full stun damage bar, you fall unconscious. Any damage that would take you *over* your stun damage track does the reamining damage as Physical Damage